On 2017-10-10, at 08:54, Ed Jaffe wrote: > On 10/10/2017 7:45 AM, Paul Gilmartin wrote: >> >> Slightly more feasible would be an option on LOCTR declaring that only >> code or only data may oppear governed by that LOCTR, and that code LOCTRs >> must >> not be overwritten. > > I LIKE that!!! > "Overwriteable" could be an additional option.
>> Some non-z architectures have additional segment protection enforcing the >> distinction between code segments and data segments at execution time. > > And z/Architecture supports this as well. That's why we have the > EXECUTABLE=YES|NO keyword on the STORAGE and IARV64 macros: > ... Damn! I've learned so little since MVS/XA. That option is half of it. Is there no complementary DATA=YES|NO? DEC TOPS-10 had such a protection on files. A file marked execute-only could not be read, only executed. That was touted as a means of IP protection. And IIRC the storage into which such a file was loaded could not be dumped (prohibiting disassembly and reverse-engineering). -- gil
